Laboratory diagnosis of Syphilis caused by Treponema pallidum 4.86/5 (14)

Laboratory diagnosis of Syphilis caused by Treponema pallidum

Laboratory diagnosis of Syphilis caused by Treponema pallidum Specimen Samples collected from ulcers and lesions should not be contaminated with blood, microorganisms, or tissue debris. Polymerase chain reaction (PCR) samples should be collected on a sterile Dacron or cotton swab and placed in a cryotube containing nucleic acid transport medium or universal transport medium. Tissue […]

Laboratory diagnosis of Listeriosis caused by Listeria monocytogenes 4.04/5 (23)

Laboratory diagnosis of Listeriosis caused by Listeria monocytogenes

Laboratory diagnosis of Listeriosis caused by Listeria monocytogenes Specimens: Cerebrospinal fluid (CSF), Blood Microscopy Gram-stain preparations of cerebrospinal fluid (CSF) typically show no organisms because the bacteria are generally present in concentrations below the limit of detection (e.g., 10ˆ4 bacteria per milliliter CSF or less). If the Gram stain shows organisms, they are intracellular and extracellular […]

Pathogenesis and Clinical manifestations of Treponema pallidum 4.65/5 (17)

Pathogenesis and Clinical manifestations of Treponema pallidum

Pathogenesis of Treponema pallidum The two major routes of transmission of Treponema pallidum are sexual and transplacental. Sexual exposure to a person who has an active syphilitic chancre carries a high probability of acquiring syphilis. The organisms enter a susceptible host by penetration of intact mucous membranes or the minute abrasions in the skin surface […]

Pathogenesis and Clinical manifestation of Gardenerella vaginalis 4.76/5 (21)

Pathogenesis and Clinical manifestation of Gardenerella vaginalis

Pathogenesis of Gardenerella vaginalis A. Adherence of G. vaginalis to Host Epithelium: Initial Steps in Invasion The initial steps of establishing infection include adherence to host receptor sites, production of cytotoxic substances specific for host cells, and biofilm formation. vaginais  produces  vaginolysin, a cholesterol-dependent cytolysin, for human cells and encodes a pore-forming toxin that binds […]

Laboratory diagnosis, treatment and prevention of Tuberculosis 4.43/5 (28)

Laboratory diagnosis, treatment and prevention of Tuberculosis

Laboratory diagnosis of Tuberculosis caused by Mycobacterium tuberculosis Specimen and processing sputum, bronchial washings, brushings or biopsies or early morning gastric aspirates, Cerebospinal Fluid (CSF), urine Specimens from sputum and other nonsterile sites should be liquefied with N-acetyl-L-cysteine decontaminated with NaOH (kills many other bacteria and fungi), neutralized with buffer, and concentrated by centrifugation. Specimens […]

Laboratory diagnosis of Bacterial vaginosis caused by Gardnerella vaginalis 4.36/5 (25)

Laboratory diagnosis of Bacterial vaginosis caused by Gardnerella vaginalis

Laboratory diagnosis of Bacterial vaginosis caused by Gardnerella vaginalis Specimen: Vaginal discharge specimen A. Direct Microscopic Examination Bacterial Vaginosis (BV) is characterized by a foul-smelling discharge. A diagnosis/confirmation is done microscopically by examination of gram stains to detect change in vaginal ecology. A smear of vaginal fluid or vaginal swab is gram stained which reveals […]

Pathogenesis and Clinical manifestation of Mycobacterium tuberculosis 4.5/5 (20)

Pathogenesis and Clinical manifestation of Mycobacterium tuberculosis

Virulence factors of Mycobacterium tuberculosis A. Mycolic acid and Lipoarabinomannan (LAM) Waxy layer that protects the bacteria from many host factors and also to many antibiotics including beta lactamases. Muramyl dipeptide (from peptidoglycan) complexed with mycolic acids can cause granuloma formation, phospholipids induce caseous necrosis. LAM is structurally and functionally related to the O antigenic […]

Laboratory Diagnosis, Treatment and Prevention of Shigella dysenteriae 4.23/5 (13)

Laboratory Diagnosis, Treatment and Prevention of Shigella dysenteriae

Laboratory Diagnosis of Shigella dysenteriae Specimens: stool, mucus flecks, and rectal swabs for culture. Large numbers of fecal leukocytes and some red blood cells often are seen microscopically. Microscopic examination Microscopic examination of stool smears reveals higher number of PMN cells. They are Gram negative small rod shaped, non-motile, non-capsulated. Culture and biochemical analysis The […]

Pathogenesis and Clinical Manifestation of Neisseria gonorrhoeae 4.88/5 (17)

Pathogenesis and Clinical Manifestation of Neisseria gonorrhoeae

Virulence factors or antigenic structures of Neisseria gonorrhoeae A. Pili Pili are the hair like appendages that extend up to several micrometers from the gonococcal surface. It mediates the exchange of genetic material between strains and attachment to human mucosal cell surface, invasion of host cells, and survival through the inhibition of phagocytosis. Two types: […]

Laboratory Diagnosis, Treatment and Prevention of Bacillus cereus 4.77/5 (13)

Laboratory Diagnosis, Treatment and Prevention of Bacillus cereus

Laboratory Diagnosis of Bacillus cereus SPECIMENS: Faeces, vomitus, remaning food (if any), eye specimen (corneal swab) DIRECT DETECTION METHODS Microscopically the organisms appear as large gram positive rods in singles, pairs, or serpentine with square ends after Gram staining. Endospores formation are seen as unstained oval or round region within centre of cell. Spores are oval […]

Clinical manifestation and Pathogenicity of Bacillus cereus 4.8/5 (10)

Clinical manifestation and Pathogenicity of Bacillus cereus

Clinical manifestation of Bacillus cereus A. Food poisoning Two forms of food poisoning: vomiting disease (emetic form) and diarrheal disease (diarrheal form). Emetic form The emetic form of disease results from the consumption of contaminated rice. Most bacteria are killed during the initial cooking of the rice, but the heat-resistant spores survive. If the cooked […]

Virulence factors and Clinical manifestation of Staphylococcus aureus 4.85/5 (13)

Virulence factors and Clinical manifestation of Staphylococcus aureus

Virulence factors of Staphylococcus aureus A. Cell wall components Polysaccharide Capsule: inhibits phagocytosis Peptidoglycan: activates complement, IL-1, chemotactic to PMNs Teichoic acid: species specific, mediate binding to fibronectin Protein A: It binds to the Fc region of IgG and complement ,exerting an anti-opsonin effect. Fibronectin binding protein(FnBP): promote binding to ,mucosal cells and tissue matrices. […]

Cultural and Biochemical characteristics of Staphylococcus aureus 4.69/5 (26)

Cultural characteristics of Staphylococcus aureus Staphylococci grow readily on most bacteriologic media under aerobic or microaerophilic conditions. Colonies on solid media are round, smooth, raised, and glistening. S. aureus usually forms gray to deep golden yellow colonies. Mannitol Salt Agar: circular, 2–3 mm in diameter, with a smooth, shiny surface; colonies appear opaque and are often […]

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